Wireless communication systems are known to include a plurality of communication units, a limited number of wireless communication resources, and a communication resource controller. A typical communication unit, which may be a mobile radio, portable radio, or radio/telephone, offers its user a variety of features, such as group calls (i.e., one-to-many communications), telephone interconnect calls (i.e., one-to-one communications), and data communications. To access one of these services, the user must request access to one of the limited number of wireless communication resources and specify the type of service requested. This request is sent from the communication unit to the communication resource controller via a control channel, wherein the control channel is one of the communication resources that has been selected to function as the control channel. Upon receiving the request, the communication resource controller determines whether this particular communication unit is authorized to access the requested service and, if so, whether a communication resource is available for allocation. When both conditions are positive, the communication resource controller allocates a communication resource to the requesting communication unit such that the user can access the requested service.
In addition to allocating a communication resource, the communication resource controller may also need to establish a communication path within a public data communication interconnect system, such as a public switch telephone network (PSTN), to complete the service request. For example, if the requested service is for a data communication, in which the user is requesting that a data file be transferred to it via the wireless communication system, the communication resource controller would need to allocate a wireless communication resource to the requesting communication unit and also establish a wireline communication path with the holder of the requested data file via the public data system. Once both of these communication paths (i.e., the wireless path and the wireline path) have been established, the requested data file can be transferred to the requesting communication unit.
The above described data transfer is becoming more and more common as technological advances occur in both the wireless art and the wireline art. These technologic advances are allowing more data to be transferred in less time via data compression, time division multiplexing, quadrature amplitude modulation techniques, ADSL, MPEG standards, ISDN, and spread spectrum techniques. As the amount and frequency of data transmissions increase, so does the chance for illicit reception of the data. Illicit reception of data transmissions, which may include video data (i.e., movies), audio data (i.e., music or conversations), data files (e.g. police files, books, etc.), occur by having an RF receiver in range of a wireless communication system to receive the data transmissions. Recall that for a wireless transmission, an antenna transmits the data in a radial pattern, such that any properly tuned receiver within the radial pattern may receive the transmission.
In a typical wireless communication system, before the data is transmitted, the requesting communication unit or units are addressed via the control channel and instructed to affiliate with another communication resource to receive the data transmission. Even though all the communication units within range of the control channel's antenna receive the addressing information, only the communication unit or units that are addressed will affiliate with the communication resource. In an ideal system (i.e., one without units illicitly receiving data transmission), only the authorized communication units receive the requested data. Unfortunately, there are few, if any, ideal systems left, thus illicit reception is a real and serious problem costing the owners of the data millions of dollars in lost revenue.
Therefore, a needs exists for a method and apparatus that prevents unauthorized reception of wireless data transmissions based on the sensitivity of the data being transmitted.